1. Field of the Present Invention
The present invention relates generally to the automation of a door closer unit, and in particular, to an automated door closure system that holds open and subsequently releases a door for user convenience.
2. Background
Secondary doors such as storm, security, and screen doors are commonly installed in front of an exterior door to protect the exterior door from weather, to prevent insects from entering the building, and/or for security. Many of the secondary doors currently on the market have a closing device, sometimes referred to herein as a “door closer,” to ensure that the door gradually closes when not held open.
One common, inexpensive closing device is a pneumatic door closer that includes a tubular housing, typically in the form of a cylinder, which contains, and operates with the use of, air, fluid, springs, and/or the like to control the closure of a door. These door closers function with an operating rod extending from one end of the cylinder. Such a closure device is typically disposed between the secondary door and the primary exterior door, with the end of the cylinder mounted to the storm door, using a mounting plug and mounting bracket, and the rod extending from the other end of the door closer and connected to the primary door frame. The rod is connected to a piston or spring mechanism inside the cylinder. Opening the secondary door exerts force on the rod, causing it to be withdrawn from the cylinder and causing the piston and/or spring mechanism to compress in the cylinder. When force is released from the rod (i.e., when the user releases the door), the force applied by the spring and/or piston mechanism causes the end rod to be pulled back into the cylinder, causing the door to close. The spring and/or piston mechanism also regulates the speed at which rod is withdrawn into the cylinder (and thus at which the door is allowed to close). In many cases, a valve or the like may be provided to adjust this speed.
The end rod usually includes a locking key that can be used to keep the secondary door open. Conventionally, the locking key is a hardened plate with two angled portions and a central aperture through which the rod passes. With the door open, and the end rod extended from the cylinder, a user can slide the locking key along the rod to a desired position, usually against the end of the cylinder. When the door is released against the locking key such that the two angled portions are each pressed against the end of the cylinder, the edges of the central aperture are forced against the rod and held there by friction, thereby preventing the rod from being withdrawn any further into the cylinder. Because the rod is thus prevented from returning into the cylinder, the door is prevented from closing. To close the door, the locking key is manually adjusted by orienting the locking key to be perpendicular to the rod, thus releasing the tension between the locking key and the cylinder and allowing the locking key to slide easily along the rod once again. With the locking key out of the way, the rod can withdraw into the cylinder once again and the door may be closed.
Unfortunately, keeping a secondary door open thus requires manual action by a user to move the locking key along the end rod. Also, when a door is currently in its open state, the user must manually re-position the locking key in order to close the door. Adjusting the locking key to keep a secondary door open can be an inconvenience for the user. For example, a person carrying items in or out of the house may struggle to open the door and hold onto the items. Furthermore, a person limited in mobility, strength, or height may struggle or not be able to move the locking key. Although various improvements have been made to standard door closers in an attempt to partially automate the “hold open” feature, all such improvements fail to completely automate the “hold open” and release-to-close features. Expensive automatic secondary doors are also available, but these usually require professional installation and are not meant to directly replace the conventional storm door, or screen door.
Accordingly, it is believed that a need exists for an inexpensive, easy to install, and/or otherwise improved closing device which holds open and subsequently closes a secondary door without the need for the user to take additional action. It is believed that one or more of these needs and other needs are addressed by one or more aspects and features of the present invention.